Okay, these are some guidelines that I'm going to be setting for creating your trainer. The trainer itself really doesn't have much for requirements, and most of these rules will actually apply to the Pokemon, but just keep them in mind.

No Powers
Remember, your Pokemon are the ones doing the battling, not you. I would let you become psychic because that's canon in the Pokemon world, BUT that would be unfair to everyone else. So, for basically, powers are a no no.

No Legendaries
This one seems a little obvious to me, and it seems to be the general consensus, but just in case someone actually needs to be told, legendaries do not belong in your Pokemon roster. Not only is this a balance issue, but it would conflict with the story as well. The only Pokemon trainer that has ever successfully captured a legendary Pokemon was Red, who captured Mewtwo so the Pokemon would not wreak havoc on the world.

No Levels
Everyone making up their own levels for their Pokemon was getting kind of rediculous, so after some discussion with hpkomic, I've decided to abolish the level system all together.

Star Pokemon
However, hpkomic also suggested that each trainer have one star Pokemon, their sidekick and absolute best, essentially. This star Pokemon is a cut above the rest in your roster, showing how much your trainer has put into training and befriending this one. This Pokemon is to your trainer what Pikachu is to Ash in the anime.

Have fun!
Don't forget to be creative with your trainer's design, and have fun with it all!